Is the Metallic Color of Stainless Steel Crown Satisfying for Cooperative Children and their Parents? a Preliminary Study

Statement of the Problem: Currently, the demand for tooth-colored restorations in children and young adults is increasing. Stainless steel crown (SSC) is the most common restoration for decayed primary molars. Given the dark metallic color of SSC, the esthetic appearance of this restoration is poor and subsequently their acceptance is still a matter of debate. Purpose: This study was conducted to evaluate the effect of restoration’s color on children’s daily living conditions and compare the clinical and radiographic success rates of composite resins with SSC in primary molars. Materials and Method: This clinical trial study was performed on 70 primary molars in 44 healthy 4- to 7-year-old children. The children were randomly divided into two groups restored with SSC and restored with composite resin. Two researcher-made questionnaires were used to assess the children’s satisfaction concerning the appearance and color of restoration. The data were analyzed with SPSS 20 using chi-squared, Fisher’s, and Mann-Whitney U tests. The significance level was set at p< 0.05. Results: Children’s satisfaction with restoration color in the treatment session was 75% in the SSC group and 85% in the composite resin group. However, the difference was not statistically significant (p= 0.246). After one year of follow-up, the satisfaction rate decreased to 69% in the SSC group and increased to 90.6% in the composite resin group, with a significant difference (p< 0.001). Moreover, the frequency of clinical success was 95% in the SSC group and 96.7% in the composite resin group, with no statistically significant difference (p= 0.749). The frequency of radiographic success was 87.5% in the SSC group and 100% in the composite resin group; this difference was not significant (p= 0.061). Conclusion: The results verified that restoration color was not important for cooperative children in the treatment session. However, after one year, children who received composite resin restorations were pointedly more satisfied than those who were treated with SSC restorations.


Introduction
Aligned and white teeth with a proper contour are essential components of facial beauty and esthetics. Having these criteria, human face would be more attractive which consequently affects individual's self-confidence and social relationships [1]. Children are aware of their appearance and beauty of their teeth. According to a deep-rooted view, perception and attention to beauty are completed at eight years of age [2]. However, new studies in the child psychology field challenge this point of view, and allege that by increasing social media activity, children at the age of 3-5 would be aware of their selfimage [2].
In dental practice, the acceptance and satisfaction with the color of restoration in children can be influenced by their gender and race [3] as well as parent's level of education [4]. All the time more, parents are looking for esthetic restorations for treatment of their children's teeth [5]. The opinions of parents and dentists regarding the ideal treatment can be dissimilar; however, understanding these differences would lead to better communication and appropriate treatment, particularly in children with sensitive parents [6]. The psychological benefits of improving oral esthetic are a priority over other dental treatments in many individuals [7] since it has been demonstrated that dental esthetic problems in childhood and adulthood would have a pronounced effect on an individual's psychological development [8].
Dental practitioners should provide sufficient information for their patients regarding each possible treatment option and incorporate their desires and needs into their treatment plan since these treatments and their complications would influence their patients' live [9].
The composite resins are esthetic restorations for the crown of primary molars that reduce the need for significant tooth preparation and their retention increase due to their micromechanical bond to the tooth [10]. However, some of their disadvantages are their restorative failure due to secondary caries and their high technical sensitivity. Therefore, in non-cooperative children or in cases that moisture control is critical, the efficiency of composite resin restoration is potentially low [11].
Despite improvements in the physicochemical properties of dental composite resins, there are significant concerns for their intrinsic toxicity [12]. Some components of restorative composite resins are released in the oral environment initially during the polymerization reaction and later due to the degradation of the material. In vitro and in vivo studies have clearly shown that these components of restorative composite resins are toxic [12].
Parents and children prefer esthetic restorations over stainless steel crown (SSC) [3]. SSCs do not satisfy parents concerned about esthetics [13]. Some parents are even repulsed by the metallic appearance of SSCs [2]. The age of esthetic perception in children has de-creased and SSC restorations cannot provide desired beauty; moreover, limited research have been performed to study the importance of esthetic factors related to the oral cavity in children. Therefore, this study aimed to preliminary study the cooperative children and their parents' views regarding the color in two groups of composite resin and SSC restoration over one year. In addition, considering the improvements in the properties of composite resin restorative materials and the temporary nature of primary teeth, the study intended to investigate and compare their clinical and radiographic success rate over one-year of follow-up.

Materials and Method
The present randomized clinical trial study was con- The interval between their visits was a maximum of one week. In the next visit, the children were divided into composite resin and SSC groups for restoration based on odd and even numbers. The children's primary molars were isolated with a rubber dam, followed by pulp therapy (pulpotomy or pulpectomy as needed) by a postgraduate student in pedodontics.
In the session of restoration, a questionnaire was proposed to assess the parents and children's satisfaction with the appearance and color of the restoration.
Then, the effect of restoration's color on the child's daily living conditions at 3-, 6-and 12-month of followup was assessed, and the parents' satisfaction with the appearance of the restored tooth was evaluated through another questionnaire in the 12-month follow-ups.
These two researcher-made questionnaires were based on a previous study [14]. For evaluation of the questionnaire's validity, 10 dental specialists reviewed the contents of the questions, which consequently one question was removed, and five questions were re- Finally, the clinical and radiographic success rates of the 12-month follow-ups were evaluated.

Restorative steps in composite resin and SSC groups SSC
After checking the occlusion, the adjacent teeth were separated with a wooden wedge (Mina, Iran). The proximal surfaces were prepared to free the contact with adjacent teeth with a sterile needle bur (Tizkavan, Tehran, Iran) in a high-speed handpiece (NSK, Japan) under water spray. Then, the cusps and occlusal surface were prepared using a sterile bur (Tizkavan, Tehran, Iran) in a high-speed under water spray. A 1-mm space was created with the opposite tooth. The smallest crown size (3M, USA) that completely covered the prepared tooth was selected, contoured, and crimped if necessary and cemented with glass-ionomer (GC-Fuji, Japan).

Composite resin restoration
After checking the occlusion, complete removal of caries and unsupported enamel was carried out using a sterile fissure bur (Tizkavan, Tehran, Iran) in a high-

Results
This experimental study was performed on 70 teeth in 44 children with 4-7 years of age with a mean age of 5.29± 1.2 years in both SSC and composite resin groups over one year. According to Table 1, the demographic

Discussion
This study showed that the color of the restoration in the treatment session is important for parents, and after a year, it was not very important for them. However, in children, it was the opposite. The children's friends see the different colors of the tooth in their mouth, and their  Utami et al. [17] reported that 90% of children had positive attitudes toward SSC restoration, and they accepted SSC. However, only 53.5% of parents accepted SSC restorations [17]. Akhlaghi et al. [14] evaluated the attitudes of parents and children towards SSC and found that 81.3% of children were satisfied with the appearance of the SSCs, and 77.6% were happy with the metal teeth. However, only 30% of parents were satisfied with the appearance of the crown [14]. According to a study by Zimmerman et al. [18], the main concerns of parents about metal crowns were related to esthetics, cost, toxicity, and durability of these restorations, respectively.
The reason for the different reactions of children and parents to the color of the restored tooth might be that improving the function and eliminating children's pain leads to a sense of satisfaction in the parents, which later decreases their sensitivity and attention to the tooth color. However, the child suffers from possible psychological effects due to the dark color of SSC, and the longer the SSC is in the mouth, the more unpleasantly the child experiences the daily events due to the metallic color of the crown.
In the current study, the clinical and radiographic success rate of composite resin and SSC restoration in the one-year follow-up was similar, which could be due to employment of bulk-fill composite resin, combined use of flow and packable composite resin, and the use of orthodontic bands instead of a matrix tape. Banding was used to save time and eliminate the time-consuming steps to place a matrix tape to prepare the tooth for the composite resin restoration. The band had a proper gingival adaptation and an interproximal contour. Orthodontic braces have formerly been used to restore class II Table 3: Frequency distribution and comparison of parents and children's answers to the questions of two questionnaires: satisfaction with the color of restoration and the effect of tooth color on the daily living conditions of the child in the follow-up visits in the two groups cavities in children [19]. Alyahya et al. [20] reported that the durability of composite resin restorations in class II cavities did not differ between 41.3 months and 45.6 months [20]. However, Zahdan et al. [21] retro The results showed that the composite resin was not different from SSC in terms of durability, margin problems, and recurrent caries in 6-and 18-month followups. However, in a 24-month follow-up, SSC was superior to composite resin restoration [22]. In this study, the bulk-fill composite resin was used, which facilitates and increases the speed of tooth restoration in children. These composite resins can be cured at depths >4 mm while exerting slight shrinkage stress to the cavity walls [23].
High curing depths of these composite resins reduces the number of composite resin layers, decreases the curing time, which is especially important in pediatric dentistry and subsequently reduces the risk of contamination, and improves the cooperation between child and dental practitioner [24]. The use of flowable composite resin as a liner and then the use of packable composite resins effectively reduce microleakage in the gingival margins [25]. Flowable composite resins have been proposed as a cavity liner with well adaptation to the cavity microstructure irregularities, improved marginal adaptation, reduced microleakage; all these advantages leads to lower rates of recurrent caries and restoration failure [26].
Since the age of esthetic appraisal in children has decreased and children in the modern world pay attention to their appearance from 3 to 5 years of age, dentists should also pay attention to their opinion in this task about esthetic and mind their opinion in choosing the restoration color. One of the limitations of this study was finding children who were eligible for the study, who had eight vital primary molars with extensive multi-surface caries, and the restoration of all eight teeth with composite or SSC could have the maximum impact on the child's living conditions. However, in this study, children with at least one primary molar up to a maximum of eight primary molars with extensive and multisurface caries were included.
Further studies are suggested to evaluate more realistic and broader dimensions of the effects of SSC metallic color on daily living of children by consulting children's psychologists. Moreover, since a one-year period is short time for evaluating a restoration in the patient's oral cavity, subsequent studies can be designed with longer follow-up periods.

Conclusion
Although the color of restoration is not important for children in their first encounter, they were significantly more satisfied with the white color of composite resin compared to the metallic color of SSC over time. Therefore, it seems that the color of tooth restoration, as one of the esthetic criteria, is considered even at young ages.
On the other hand, parents who reacted to the color of their child's restoration in the same session and were more satisfied with the white color of the composite restoration right after seeing the tooth than the SSC metallic color did not show any sensitivity to the color of their children's teeth after a year. The application of bulk-fill flowable and bulk-fill packable composite resin resulted in clinical and radiographic success similar to SSC for restoring primary molar teeth.